The present invention relates to reinforced cementitious panels or boards comprising a cementitious core, the boards or panels being fabric-reinforced at the surface thereof. More particularly, it relates to panels or boards whose opposed broad faces are reinforced by a network of fibers which may be adhered at a surface thereof e.g. be adhered to or embedded at or just below the cementitious surfaces thereof. Still more particularly, the present invention relates to a cementitious board whose longitudinal edges are reinforced by a network of fibers. Such a cementitious panel or board may, for example, be a light-weight concrete panel, a tile backerboard panel, or the like.
The word xe2x80x9ccementitiousxe2x80x9d as used herein is to be understood as referring to any material, substance or composition containing or derived from a hydraulic cement such as for example, portland cement (see below). The term xe2x80x9cslurryxe2x80x9d is to be understood as referring to a flowable mixture, e.g. a flowable mixture of water and a hydraulic cement. The term xe2x80x9ccorexe2x80x9d is to be understood as referring to a mixture of a hydraulic cement, water and aggregate (such as sand, expanded shale or clay, expanded polystyrene beads, slag and similar materialsxe2x80x94see below), as well as, if desired or necessary, additional additives such as foaming agents, modifiers and the like.
The term xe2x80x9cslurry pervious reinforcing meshxe2x80x9d is to be understood as characterizing a mesh as being suitable for use in the preparation of a concrete panel by having openings sufficiently large to permit penetration of a cementitious slurry or a slurry component of a core mix into and through the openings so as to permit (mechanical) bonding of the mesh to the core either by for example by being cemented to the core or by being embedded in a face or surface of the core of a panel.
The expression xe2x80x9cslurry impervious meshxe2x80x9d is to be understood as characterizing a mesh as being water impervious or as being able to filter out or inhibit the penetration of slurry solids therein so as to inhibit (mechanical) bonding of the mesh to the core by the cementitious material.
It is to be understood herein that the expression xe2x80x9cadhered toxe2x80x9d in relation to a reinforcing mesh component (e.g. mesh, mat, fabric, tissue, etc.) means that the mesh component may be adhered for example to a face or surface by any suitable means such as by an adhesive, by a cement, or by being embedded in, at or immediately beneath the surface of a respective face or surface such that the mesh component is effectively bonded to the core, i.e. a hardened or set cementitious material extends through the interstices of the fibrous layers.
Keeping the above immediate definition in mind, it is to be understood herein that the expression xe2x80x9cadhered to said core atxe2x80x9d in relation to a reinforcing mesh component (e.g. mesh, mat, fabric, tissue, etc.) means that the mesh component does not extend beyond the specified face, area, region, or the like, i.e. it is restricted to the specified face region etc. Thus for example in relation to a broad face reinforcing mesh indicated as being adhered to a core at a broad face means that the mesh is restricted to being adhered to the broad face.
The word xe2x80x9cwovenxe2x80x9d as used herein is to be understood as characterizing a material such as a reinforcing mesh (e.g. mat, fabric, tissue or the like) as comprising fibers or filaments which are oriented; oriented fibers or filaments being disposed in an organized fashion.
The word xe2x80x9cnon-wovenxe2x80x9d as used herein is to be understood as characterizing a material such as a reinforcing mesh (e.g. mat, fabric, tissue or the like) as comprising fibers or filaments which are oriented (as described above) or which are non-oriented; non-oriented fibers or filaments being disposed in random fashion.
In general, a reinforced cementitious panel or board may be fastened to a wall frame for the construction of a wall and particularly for the construction of a wall where high moisture conditions are to be encountered. Such a wall panel may provide a long lasting substrate for humid or wet areas such as shower rooms and bath rooms and provide high impact resistance where there is high number of people circulating. For example, such a reinforced cementitious panel or board may be used as a substrate for ceramic tile in bath rooms, shower rooms, locker rooms, swimming pool rooms and other areas where the wall are subject to frequent splashing of water and high humidity. Once the panel is affixed to a wall frame a wall facing material may, as desired or necessary, in turn be affixed thereto such as, for example, ceramic tile, thin brick, thin marble panels, stucco or the like. Reinforced cementitious panels or boards having cores formed of a cementitious composition with the faces being reinforced with a layer of fabric bonded thereto are known; see for example U.S. Pat. No. 1,439,954, U.S. Pat. No. 3,284,980, U.S. Pat. No. 4,450,022, U.S. Pat. No. 4,916,604, etc.
Various processes for the preparation of such cementitious boards or panels are also known. British Patent application no. 2,053,779 for example discloses a method for the continuous production of a building board which comprises advancing a pervious fabric on a lower support surface, depositing a slurry of cementitious material onto the advancing fabric, contacting the exposed face of the slurry with a second fabric such that the slurry penetrates through the fabric to form a thin, continuous film on the outer faces of the fabric.
Because of its cementitious nature, a cement board may have a tendency to be relatively brittle.
Cementitious wall board or panels are often attached at their marginal edges to the building framework with for example fasteners such as nails, screws and the like. When fasteners for example such as screws or nails are installed near the edge (less than xc2xdxe2x80x3), it is highly desirable that the edge be able to retain sufficient structural integrity such that the panel remains attached to a wall member, i.e. that the panel have a relatively high fastener pull resistance such that the fastener will not laterally pull through or break through the board edge.
It is known to augment the strength of the border edge regions by wrapping the fabric covering one broad face of the board around the edge so as to overlay the fabric on the other opposite broad side thereof.
U.S. Pat. No. 4,916,004, for example, discloses a cement board having a woven mesh of glass fibers immediately below each face thereof, the mesh in one broad face continuing under the surface of both longitudinal edge faces, with the two meshes in an abutting or an overlapping relation along the longitudinal margins of the opposite face. Please also see U.S. Pat. Nos. 5,221,386 and 5,350,554.
U.S. Pat. No. 4,504,533, for example, discloses a gypsum board in which a composite web of a non-woven fiberglass felt and a woven fiberglass mat covers the upper and lower faces of a gypsum core while only the lower non-woven fiberglass felt is wrapped around the longitudinal edges of the gypsum core so that the non-woven fiberglass felt extends partially inward on the upper face of the core such that the border edge regions are covered only by non-woven fiberglass felt.
U.S. Pat. No. 1,787,163 on the other hand discloses a gypsum board in which side edge portions include a separate strip of U-shaped fabric extending from one broad face across the edge to the other broad face; the fabric legs of this separate strip each extend into the plaster core body beneath a respective sheet of fibrous material covering a respective broad face, i.e. the legs are submerged below the broad face and in particular below the broad face reinforcement means.
The problem common to all methods of production of fiber mesh reinforced cementitious panels still remains as to how to effectively reinforce longitudinal edges of cementitious panels. The problem is particularly difficult when the economics of continuous production are desired. Glass fiber mesh, is a common reinforcing fabric and is used in the form of a fibreglass scrim. The open fibreglass scrim may be relatively easily damaged and commonly has openings sized such that the core material can pass through when sufficient force is applied, thus reducing the integrity of the board. Therefore, its edges may be particularly fragile such that special care is needed when manipulating or installing such a cementitious board or panel.
It would be advantageous to be able to have an alternate manner of making an alternative type panel configured such that when a nail, screw or like shaft fastener is inserted close to the edge of a panel the mesh reinforced edge may minimize edge break out by the nail or screw or like shaft fastener of edge and thus provide secure attachment of the panel to a framing support.
It would for example be advantageous to be able to customize the reinforcement characteristics of the longitudinal edge area of a panel by being able to choose a desired reinforcement mesh component which is different from the mesh used for the broad faces of a wall panel core and being able to choose a desired attachment technique to the longitudinal edge. It would be advantageous for example too be able to have a panel or board wherein the edge reinforcing mesh may be different from the broad face reinforcing mesh (e.g. of a different substance, of different mesh openings, of non-oriented fibers or filaments rather than oriented fibers or filaments).
It would be advantageous to be able to have a panel wherein the longitudinal edge face of the panel may be more or less free of cementitious material so as to allow the longitudinal edge face to be used as a support substrate for a visual indicia such as colour, images, symbols, words, etc., i.e. such that an indica would not be covered up during the manufacturing process by cementitious material.
It would be advantageous to be able to have a means of treating the side edges of the board in the course of manufacture in such a manner as to enhance its structural qualities and its use for the purposes intended. It in particular would be advantageous to be able to have a means of manufacturing the edges of the board in such a manner that it will have impact resistant edges and be able to be constructed so as to be able to offer a relatively higher lateral fastener pull resistance in the edge area than in the central core area.
The present invention in an aspect provides a cementitious panel comprising a longitudinal side edge face, a pair of opposed broad faces, a longitudinal marginal edge, a light weight cementitious core, a first broad face reinforcing mesh component, a second broad face reinforcing mesh component, and a first edge reinforcing mesh component,
each broad face comprising a marginal area bordering said longitudinal edge face
said longitudinal marginal edge comprising a marginal area of one of said broad faces, an opposed marginal area of the other of said broad faces and said longitudinal side edge face,
said first and second broad face reinforcing mesh components each being adhered to said core at a respective broad face,
said first edge reinforcing mesh component comprising an edge strip member being adhered to said core at a marginal area of said longitudinal marginal edge,
said first and second broad face reinforcing meshes and said first edge reinforcing mesh being configured and disposed such that said strip member overlaps one of said first and second reinforcing meshes in a respective marginal area of said longitudinal marginal edge.
In accordance with the present invention the reinforcing mesh overlaped by said strip member may be is offset inwardly relative to the longitudinal side edge face of said longitudinal marginal edge.
In accordance with another aspect the present invention provides a cementitious panel comprising a longitudinal side edge face, a pair of opposed broad faces, a longitudinal marginal edge, a light weight cementitious core, a first broad face reinforcing is mesh component, a second broad face reinforcing mesh component, and a first edge reinforcing mesh component,
each broad face comprising a marginal area bordering said longitudinal edge face
said longitudinal marginal edge comprising a marginal area of one of said broad faces, an opposed marginal area of the other of said broad faces and said longitudinal side edge face,
said first and second broad face reinforcing mesh components each being adhered to said core at a respective broad face,
said first edge reinforcing mesh component comprising first and second edge strip members being adhered to said core at respective opposed marginal areas of said longitudinal marginal edge,
said first and second broad face reinforcing meshes and said first edge reinforcing mesh being configured and disposed such that said first and second strip members respectively overlap the first and second reinforcing meshes in the marginal areas of said longitudinal marginal edge.
In accordance with the present invention the first and second broad face reinforcing meshes may be offset inwardly relative to the longitudinal side edge face of said longitudinal marginal edge.
In accordance with the present invention there is provided a cementitious panel comprising a longitudinal side edge face, a pair of opposed broad faces, a longitudinal marginal edge, a light weight cementitious core, a first broad face reinforcing mesh component, a second broad face reinforcing mesh component, and a first U-shaped edge reinforcing mesh component,
each broad face comprising a marginal area bordering said longitudinal edge face
said longitudinal marginal edge comprising a marginal area of one of said broad faces, an opposed marginal area of the other of said broad faces and said longitudinal side edge face,
said first and second broad face reinforcing mesh components each being adhered to said core at a respective broad face,
said first U-shaped edge reinforcing mesh component comprising first and second edge strip members and a bridging member connecting said first and second edge strip members, said first and second edge strip members being adhered to said core at respective opposed marginal areas of said longitudinal marginal edge,
said first and second broad face reinforcing meshes and said first U-shaped edge reinforcing mesh being configured and disposed such that said first and second strip members respectively overlap the first and second reinforcing meshes in the marginal areas of said longitudinal marginal edge.
In accordance with the present invention the first and second broad face reinforcing meshes may as mentioned above be offset inwardly relative to the longitudinal side edge face of said longitudinal marginal edge.
In accordance with the present invention the bridge member may be non-adhered to said core at said longitudinal side edge face.
In accordance with the present invention the first and second broad face reinforcing meshes may be offset inwardly relative to the longitudinal side edge face of said longitudinal marginal edge and a bridge member may be non-adhered to said core at said longitudinal side edge face.
In accordance with the present invention marginal area(s) may comprise an adhesion region and a non-adhesion region, said non-adhesion region(s) bordering said longitudinal side edge face(s) and the first and second edge strip members may be non-adhered to said core at respective non-adhesion regions; may be non-embedded; may be abutting appropriate faces, etc.
In accordance with a further aspect the present invention provides a cementitious panel comprising a pair of opposed longitudinal side edge faces, a pair of opposed broad faces, a pair of opposed longitudinal marginal edges, a light weight cementitious core, a first broad face reinforcing mesh component, a second broad face reinforcing mesh component, a first U-shaped edge reinforcing mesh component and a second U-shaped edge reinforcing mesh component,
each broad face comprising a marginal area bordering each longitudinal edge face
each longitudinal marginal edge comprising a marginal area of one of said broad faces, an opposed marginal area of the other of said broad faces and a respective longitudinal side edge face,
said first and second broad face reinforcing mesh components each being adhered to said core at a respective broad face,
said first and second U-shaped edge reinforcing mesh components each comprising first and second edge strip members and a bridging member connecting said first and second edge strip members, said first and second edge strip members being adhered to said core at respective opposed marginal areas of a respective longitudinal marginal edge,
said first and second broad face reinforcing mesh components and said first and second U-shaped edge reinforcing mesh components being configured and disposed such that said first and second strip members respectively overlap the first and second reinforcing meshes in the marginal areas of a respective longitudinal marginal edge.
In accordance with the present invention, as mentioned above, the first and second broad face reinforcing meshes may be offset inwardly relative to the longitudinal side edge faces of said longitudinal marginal edges.
In accordance with the present invention as mentioned above a bridge member(s) may be non-adhered to said core at respective longitudinal side edge face(s).
In accordance with the present invention as mentioned above the first and second broad face reinforcing meshes may be offset inwardly relative to the longitudinal side edge faces of said longitudinal marginal edges and bridge members may be non-adhered to said core at respective longitudinal side edge faces.
In accordance with the present invention as mentioned above marginal areas may comprise an adhesion region and a non-adhesion region, said non-adhesion regions bordering said longitudinal side edge faces and first and second edge strip members may be non-adhered to said core at respective non-adhesion regions.
In accordance with the present invention the first and second broad face reinforcing mesh components may each be embedded in a respective broad face of said core and first and second edge strip members may be cemented to said core at respective opposed marginal areas of a respective longitudinal marginal edge.
In accordance with the present invention as mentioned first and second broad face reinforcing meshes may be offset inwardly relative to the longitudinal side edge faces of said longitudinal marginal edges and bridge members may be non-adhered to said core at respective longitudinal side edge faces.
In accordance with the present invention a bridge member(s) may be are non-adhered to said core at respective longitudinal side edge face(s).
In accordance with the present invention as mentioned first and second broad face reinforcing meshes may be offset inwardly relative to the longitudinal side edge faces of said longitudinal marginal edges, bridge members may be non-adhered to said core at respective longitudinal side edge faces.
In accordance with the present invention as mentioned marginal areas may comprise an adhesion region and a non-adhesion region, said non-adhesion regions bordering said longitudinal side edge faces and first and second edge strip members may be non-adhered to said core at respective non-adhesion region.
In accordance with the present invention a core may have an average unit weight of not more than about 120 pounds per cubic foot.
In accordance with the present invention first and second broad face mesh components may be of a non-woven oriented mesh and the U-shaped edge reinforcing mesh component may be of a non-woven non-oriented reinforcing mesh.
In accordance with the present invention a panel may be provided with reinforced broad side face as follows: the web of fabric is deposited onto a supporting web member (e.g., a plastic protective film), a cementitious slurry is fed to the upper surface of the web and then is spread uniformly over the web in controlled amount by means of a doctor (blade, bar or roller) adjustably spaced from the supporting member. The web is drawn out of the slot formed by the doctor and supporting member, thereby applying the desired coating of slurry to the first reinforcing mesh; the core mix is then applied. Then the second web is deposited upon the upper face of the core layer; vibrating the layer of slurry in contact with the fabric or web until slurry penetrates the web and the latter is completely embedded.
In accordance with a different aspect the present invention provides a method for manufacturing a reinforced cementitious panel having a reinforced longitudinal edge comprising:
forming a first slurry comprising a cementitious material and water;
forming a core mix comprising a cementitious material, lightweight aggregate and water
providing a panel forming support substrate;
laying over said panel forming support substrate a band of reinforcing mesh;
laying a first sheet of reinforcing mesh over said panel forming support substrate such that said sheet of reinforcing mesh overlaps said band at an outer marginal portion of said first sheet of reinforcing mesh,
depositing said first slurry on said first sheet of reinforcing mesh and distributing it across the breadth of said first sheet of reinforcing mesh so as to form a slurried reinforcement layer of predetermined thickness such that the first sheet of reinforcing mesh is embedded in said slurried reinforcement layer;
depositing said core mix on said slurried reinforcement layer and distributing the core mix across said first sheet of reinforcing mesh so as to form a core layer of predetermined depth having an upper broad surface
laying a second sheet of reinforcing mesh over said core layer such that said second sheet of reinforcing mesh is embedded in said upper broad surface and overlies said first sheet of reinforcing mesh.
In accordance with another aspect the present invention provides a method for manufacturing a reinforced cementitious panel having a reinforced longitudinal edge comprising:
forming a first slurry comprising a cementitious material and water;
forming a core mix comprising a cementitious material, lightweight aggregate and water
providing a panel forming support substrate;
laying a first sheet of reinforcing mesh over said panel forming support substrate,
depositing said first slurry on said first sheet of reinforcing mesh and distributing it across the breadth of said first sheet of reinforcing mesh so as to form a slurried reinforcement layer of predetermined thickness such that the first sheet of reinforcing mesh is embedded in said slurried reinforcement layer;
depositing said core mix on said slurried reinforcement layer and distributing the core mix across said first sheet of reinforcing mesh so as to form a core layer of predetermined depth having an upper broad surface
laying a second long sheet of reinforcing mesh over said core layer such that said second sheet of reinforcing mesh is embedded in said upper broad surface and overlies said first sheet of reinforcing mesh
laying over said upper broad surface a band of reinforcing mesh such that said band overlaps said second sheet of reinforcing mesh band at an outer marginal portion of said panel and first sheet of reinforcing mesh and is embedded in said upper broad surface.
In accordance with an additional aspect the present invention provides a method for manufacturing a reinforced cementitious panel having a reinforced longitudinal edge comprising:
forming a first slurry comprising a cementitious material and water;
forming a core mix comprising a cementitious material, lightweight aggregate and water
providing a panel forming support substrate, said panel forming support substrate being wider than the panel to be made;
laying over said panel forming support substrate a band of reinforcing mesh;
laying a first sheet of reinforcing mesh over said panel forming support substrate such that said first sheet of reinforcing mesh overlaps a predetermined portion of said first band so as to leave an outer portion of said band uncovered by said first sheet of reinforcing mesh,
depositing said first slurry on said first sheet of reinforcing mesh and distributing it across the breadth of said first sheet of reinforcing mesh so as to form a slurried reinforcement layer of predetermined thickness such that the first sheet of reinforcing mesh is embedded in said slurried reinforcement layer;
depositing said core mix on said slurried reinforcement layer and distributing the core mix across said first sheet of reinforcing mesh so as to form a core layer of predetermined depth having an upper broad surface
laying a second indefinitely long sheet of reinforcing mesh over said core layer such that said second sheet of reinforcing mesh is embedded in said upper broad surface and overlies said first sheet of reinforcing mesh,
bending the outer marginal portions of said band upwardly to an upright position,
folding upright portions of said band inwardly so as to overlap said second sheet of reinforcing mesh and such that said band defines a U-shaped edge reinforcing mesh.
In accordance with the present invention a method for the manufacture of a panel wherein said U-shaped edge reinforcing mesh comprises first and second edge strip members and a bridging member connecting said first and second edge strip members, and said bridge member is non-adhered to said core, may be carried out wherein said band has a non adhesion zone for the formation of said bridge member.
In accordance with a further aspect the present invention provides a method for manufacturing a reinforced cementitious panel having reinforced longitudinal edges comprising:
forming a first slurry comprising a cementitious material and water;
forming a core mix comprising a cementitious material, lightweight aggregate and water
providing a panel forming support substrate, said panel forming support substrate being wider than the panel to be made;
laying over said panel forming support substrate, in spaced apart parallel relation, a first band of reinforcing mesh and second band of reinforcing mesh;
laying a first sheet of reinforcing mesh over said panel forming support substrate such that said first sheet of reinforcing mesh overlaps a predetermined portion of each of said first and second bands so as to leave an outer portion of each band uncovered by said first sheet of reinforcing mesh,
depositing said first slurry on said first sheet of reinforcing mesh and distributing it across the breadth of said first sheet of reinforcing mesh so as to form a slurried reinforcement layer of predetermined thickness such that the first sheet of reinforcing mesh is embedded in said slurried reinforcement layer;
depositing said core mix on said slurried reinforcement layer and distributing the core mix across said first sheet of reinforcing mesh so as to form a core layer of predetermined depth having an upper broad surface
laying a second indefinitely long sheet of reinforcing mesh over said core layer such that said second sheet of reinforcing mesh is embedded in said upper broad surface and overlies said first sheet of reinforcing mesh,
bending the outer marginal portions of said first and second bands upwardly to an upright position,
folding upright portions of said first and second bands inwardly so as to overlap said second sheet of reinforcing mesh and such that each of said first and second bands define a U-shaped edge reinforcing mesh.
In accordance with another aspect the present invention provides a method for manufacturing a reinforced cementitious panel having reinforced longitudinal edges comprising:
continuously forming a first slurry comprising a cementitious material and water;
continuously forming a core mix comprising a cementitious material, lightweight aggregate and water
continuously advancing an indefinitely long panel forming support substrate over a support surface, said panel forming support substrate being wider than the panel to be made;
continuously laying over said panel forming support substrate, in spaced apart parallel relation, an indefinitely long first band of reinforcing mesh and an indefinitely long second band of reinforcing mesh;
continuously laying a first indefinitely long sheet of reinforcing mesh over said panel forming support substrate such that said first sheet of reinforcing mesh overlaps a predetermined portion of each of said first and second bands so as to leave an outer portion of each band uncovered by said first sheet of reinforcing mesh,
continuously depositing said first slurry on said first sheet of reinforcing mesh and distributing it across the breadth of said first sheet of reinforcing mesh so as to form a slurried reinforcement layer of predetermined thickness such that the first sheet of reinforcing mesh is embedded in said slurried reinforcement layer;
continuously depositing said core mix on said slurried reinforcement layer and distributing the core mix across said first sheet of reinforcing mesh so as to form a core layer of predetermined depth having an upper broad surface
continuously laying a second indefinitely long sheet of reinforcing mesh over said core layer such that said second sheet of reinforcing mesh is embedded in said upper broad surface so as to leave an outer marginal portion of each of said bands uncovered by said second sheet of reinforcing mesh,
continuously bending the outer marginal portions of said first and second bands upwardly to an upright position,
folding upright portions of said first and second bands inwardly so as to overlap said second indefinitely long sheet of reinforcing mesh and such that each of said first and second bands define a U-shaped edge reinforcing mesh.
In accordance with a different aspect the present invention provides an apparatus for manufacturing a reinforced cementitious panel having reinforced longitudinal edges comprising
means for forming a first slurry comprising a cementitious material and water;
means for forming a core mix comprising a cementitious material, lightweight aggregate and water
means for providing a panel forming support substrate;
means for laying over said panel forming support substrate a band of reinforcing mesh;
means for laying a first sheet of reinforcing mesh over said panel forming support substrate such that said sheet of reinforcing mesh overlaps said band at an outer marginal portion of said first sheet of reinforcing mesh,
means for depositing said first slurry on said first sheet of reinforcing mesh and distributing it across the breadth of said first sheet of reinforcing mesh so as to form a slurried reinforcement layer of predetermined thickness such that the first sheet of reinforcing mesh is embedded in said slurried reinforcement layer;
means for depositing said core mix on said slurried reinforcement layer and distributing the core mix across said first sheet of reinforcing mesh so as to form a core layer of predetermined depth having an upper broad surface
means for laying a second sheet of reinforcing mesh over said core layer such that said second sheet of reinforcing mesh is embedded in said upper broad surface and overlies said first sheet of reinforcing mesh.
In accordance with another aspect the present invention provides a method for manufacturing a reinforced cementitious panel having a reinforced longitudinal edge comprising:
means for forming a first slurry comprising a cementitious material and water;
means for forming a core mix comprising a cementitious material, lightweight aggregate and water
means for providing a panel forming support substrate;
means for laying a first sheet of reinforcing mesh over said panel forming support substrate,
means for depositing said first slurry on said first sheet of reinforcing mesh and distributing it across the breadth of said first sheet of reinforcing mesh so as to form a slurried reinforcement layer of predetermined thickness such that the first sheet of reinforcing mesh is embedded in said slurried reinforcement layer;
means for depositing said core mix on said slurried reinforcement layer and distributing the core mix across said first sheet of reinforcing mesh so as to form a core layer of predetermined depth having an upper broad surface
means for laying a second long sheet of reinforcing mesh over said core layer such that said second sheet of reinforcing mesh is embedded in said upper broad surface and overlies said first sheet of reinforcing mesh
means for laying over said upper broad surface a band of reinforcing mesh such that said band overlaps said second sheet of reinforcing mesh band at an outer marginal portion of said panel and first sheet of reinforcing mesh and is embedded in said upper broad surface.
In accordance with an additional aspect the present invention provides an apparatus for manufacturing a reinforced cementitious panel having a reinforced longitudinal edge comprising:
means for forming a first slurry comprising a cementitious material and water;
means for forming a core mix comprising a cementitious material, lightweight aggregate and water
means for providing a panel forming support substrate, said panel forming support substrate being wider than the panel to be made;
means for laying over said panel forming support substrate a band of reinforcing mesh;
means for laying a first sheet of reinforcing mesh over said panel forming support substrate such that said first sheet of reinforcing mesh overlaps a predetermined portion of said first band so as to leave an outer portion of said band uncovered by said first sheet of reinforcing mesh,
means for depositing said first slurry on said first sheet of reinforcing mesh and distributing it across the breadth of said first sheet of reinforcing mesh so as to form a slurried reinforcement layer of predetermined thickness such that the first sheet of reinforcing mesh is embedded in said slurried reinforcement layer;
means for depositing said core mix on said slurried reinforcement layer and distributing the core mix across said first sheet of reinforcing mesh so as to form a core layer of predetermined depth having an upper broad surface
means for laying a second indefinitely long sheet of reinforcing mesh over said core layer such that said second sheet of reinforcing mesh is embedded in said upper broad surface and overlies said first sheet of reinforcing mesh,
means for bending the outer marginal portions of said band upwardly to an upright position,
means for folding upright portions of said band inwardly so as to overlap said second sheet of reinforcing mesh and such that said band defines a U-shaped edge reinforcing mesh.
In accordance with the present invention an for the manufacture of a panel wherein said U-shaped edge reinforcing mesh comprises first and second edge strip members and a bridging member connecting said first and second edge strip members, and said bridge member is non-adhered to said core, may be used wherein the apparatus includes means for applying a non adhesion zone to said band for the formation of said bridge member.
In accordance with a further aspect the present invention provides an apparatus for manufacturing a reinforced cementitious panel having reinforced longitudinal edges comprising:
means for forming a first slurry comprising a cementitious material and water;
means for forming a core mix comprising a cementitious material, lightweight aggregate and water
means for providing a panel forming support substrate, said panel forming support substrate being wider than the panel to be made;
means for laying over said panel forming support substrate, in spaced apart parallel relation, a first band of reinforcing mesh and second band of reinforcing mesh;
means for laying a first sheet of reinforcing mesh over said panel forming support substrate such that said first sheet of reinforcing mesh overlaps a predetermined portion of each of said first and second bands so as to leave an outer portion of each band uncovered by said first sheet of reinforcing mesh,
means for depositing said first slurry on said first sheet of reinforcing mesh and distributing it across the breadth of said first sheet of reinforcing mesh so as to form a slurried reinforcement layer of predetermined thickness such that the first sheet of reinforcing mesh is embedded in said slurried reinforcement layer;
means for depositing said core mix on said slurried reinforcement layer and distributing the core mix across said first sheet of reinforcing mesh so as to form a core layer of predetermined depth having an upper broad surface
means for laying a second indefinitely long sheet of reinforcing mesh over said core layer such that said second sheet of reinforcing mesh is embedded in said upper broad surface and overlies said first sheet of reinforcing mesh,
means for bending the outer marginal portions of said first and second bands upwardly to an upright position,
means for folding upright portions of said first and second bands inwardly so as to overlap said second sheet of reinforcing mesh and such that each of said first and second bands define a U-shaped edge reinforcing mesh.
In accordance with another aspect the present invention provides an apparatus for manufacturing a reinforced cementitious panel having reinforced longitudinal edges comprising:
means for continuously forming a first slurry comprising a cementitious material and water;
means for continuously forming a core mix comprising a cementitious material, lightweight aggregate and water
means for continuously advancing an indefinitely long panel forming support substrate over a support surface, said panel forming support substrate being wider than the panel to be made;
means for continuously laying over said panel forming support substrate, in spaced apart parallel relation, an indefinitely long first band of reinforcing mesh and an indefinitely long second band of reinforcing mesh;
means for continuously laying a first indefinitely long sheet of reinforcing mesh over said panel forming support substrate such that said first sheet of reinforcing mesh overlaps a predetermined portion of each of said first and second bands so as to leave an outer portion of each band uncovered by said first sheet of reinforcing mesh,
means for continuously depositing said first slurry on said first sheet of reinforcing mesh and distributing it across the breadth of said first sheet of reinforcing mesh so as to form a slurried reinforcement layer of predetermined thickness such that the first sheet of reinforcing mesh is embedded in said slurried reinforcement layer;
means for continuously depositing said core mix on said slurried reinforcement layer and distributing the core mix across said first sheet of reinforcing mesh so as to form a core layer of predetermined depth having an upper broad surface
means for continuously laying a second indefinitely long sheet of reinforcing mesh over said core layer such that said second sheet of reinforcing mesh is embedded in said upper broad surface so as to leave an outer marginal portion of each of said bands uncovered by said second sheet of reinforcing mesh,
means for continuously bending the outer marginal portions of said first and second bands upwardly to an upright position,
means for folding upright portions of said first and second bands inwardly so as to overlap said second indefinitely long sheet of reinforcing mesh and such that each of said first and second bands define a U-shaped edge reinforcing mesh.
In accordance with the present invention a bridge member may be non-embedded in a longitudinal side edge face.
In accordance with the present invention a support substrate may comprise a conveyor belt (supported on tab) and a protective film. If desired or necessary the protective film may be dispensed with but in such a case it may be necessary tho coat a particular conveyor belt with agents such as anti-stick agents.
As mentioned above, in accordance with the present invention the first and second edge strip members of a U-shaped edge reinforcing mesh may be adhered to said core at respective marginal areas of a respective longitudinal marginal edge by being cemented thereto or as desired by being embedded in respective broad faces. A bridging member may as desired also be cemented to or as desired be embedded in a respective longitudinal edge face. On the other hand a bridging member need not if desired be adhered to a respective longitudinal edge face but may merely abut such face or as desired be spaced apart therefrom; in this latter case the bridging member may be water impervious such that, for example, cementitious material may not pass into or through the bridging member during the manufacture of a panel such that it is possible to for example provide the exposed side of the bridging member with a desired indica as described above.
A cementitious board or panel of the present invention may be designed to be used as a backerboard for tile, thin brick, thin stones, synthetic or natural stucco, paint, exterior insulation and finish systems or other finishes that can be applied onto concrete. It may be of interior or exterior grade and can be used in such places as kitchens, bath room, shower room, corridors, exterior wall, or any places that require water resistance and impact resistance. It may be used to construct fire resistant partition walls.
As may be understood, in accordance with the present invention a cementitious panel may have a composite or sandwich like construction wherein a cementitious core is bounded on each of its two major or broad faces by a respective reinforcing mesh component of fibrous material; each reinforcing mesh component being adhered to the panel core at a respective major face thereof.
The longitudinal edge faces of a panel may also be covered or closed off by an edge reinforcing mesh component. The edge reinforcing mesh component may be adhered to the longitudinal edge face, merely abut the longitudinal edge face or be spaced apart from the longitudinal face; this type of reinforcing mesh component may, for example take on a U-shaped configuration as discussed herein. Alternatively, if desired, the longitudinal edge face or a part thereof may be open, i.e. not covered by a reinforcing mesh material. In this latter case one or both of the marginal areas adjacent a longitudinal edge on opposite broad faces may be provided with an edge reinforcing member.
A panel in accordance with the present invention may have a longitudinal edge face which may be more or less free of cementitious material so as to allow the longitudinal edge face to be used as a support substrate for a visual indicia such as color, images, symbols, words, etc., i.e. the reinforcing mesh may be configured such that an indica support area would not be covered up during the manufacturing process by cementitious material.
The reinforcing mesh components or members thereof whether for a broad or major face or for a longitudinal edge face may take the form of a woven or non woven fabric or mesh such as a woven mesh or scrim, a non-woven mesh, a non-woven pervious mesh or mat, etc.. Suitable fiber filaments may be formed into a woven material by the employment of a suitable method such as knitting or weaving. Suitable fiber filaments may be formed into non-woven material by the employment of a suitable method such as gluing or fusion.
The reinforcing mesh for a broad face may for example take the form of a woven mesh or a non-woven oriented mesh. On the other hand a mesh for a longitudinal edge face may take the form of a non-woven mesh, in particular a non-woven non-oriented mesh.
A woven mesh for a broad face may for example be composed of glass fibers and be in the form of woven or knitted fabric or scrim. When a glass fiber network is used in conjunction with an alkaline cementitious material, for example, a highly alkaline Portland, cementitious composition, the glass fibers may be made from an alkaline resistant glass or have a protective resin coating so that damage which might result from reaction with the alkaline cementitious material, may be minimized; this may be accomplished by coating the fibers with an alkali resistant coating such as an epoxy resin. The reinforcing mesh may, for example, be a fibre-glass scrim, in particular, a woven mesh of vinyl (e.g. polyvinylchloride) coated glass-fibre yarns.
The reinforcing mesh for a broad face may, if desired, alternatively, be in the form of a non-woven oriented fabric or web, bonded with a suitable synthetic resin or by heat. The mesh may be of non-woven oriented glass fibre tissue. A non-woven glass fibre tissue may be of resin-bonded fibers or filaments, for example fibers bonded with urea-formaldehyde and may have a weight of about 2 to 4 oz. per square yard, the fibers may for example have a diameter of e.g. 10 to 20 um.
However, a woven or non-woven oriented mesh of other materials may be used for reinforcing a broad face of a panel. Such a mesh may for example be of an inorganic material such as for example, of a metal (e.g. a steel fibre) of asbestos, of alumina, of zirconia, of carbon and the like. Alternatively, a mesh may be of synthetic material such as for example of organic polymeric fibers, for example, nylon fibers, polyvinylidene chloride fibers, polyester fibre yarns coated with PVC, aramid resin fibers (e.g as sold under the trade-mark Kevlar), polyolefin fiber, e.g. polyethylene or polypropylene; of fluorinated polyolefin, e.g. polyvinylidene fluoride or polytetrafluoroethylene; or polyamide fibre; or of polyester fibre, e.g. poly(ethylene terephthalate); or of cellulosic fibre and the like.
The mesh size and the fiber diameter for a woven or non-woven oriented mesh used to reinforce the broad or major faces of the core may be selected according to the strength desired in the board and the size of the aggregate in the concrete mix. A mesh for a broad face reinforcement may, for example, have a relatively loose thread or mesh count per inch (warpxc3x97fill) such as for example, of from 4xc3x974 to 18xc3x9718, of 10xc3x978, etc. for most purposes.
In accordance with the present invention the reinforcement of the edges and margins of a cementitious board or panel may be accomplished by using a separate type of woven or non-woven mesh or mat fabric as compared with the reinforcing mesh used for the broad faces; advantageously, the reinforcing mesh for the edge face may be a non-woven non-oriented mesh. For example, a reinforcing mesh for the longitudinal edges may have relatively tight intercises as compared with a reinforcing mesh for a broad facesxe2x80x942 to 4 oz. per sq. yd.xe2x80x94; the relatively tight intercises makes attachment of the board to a wall framework with nails or screws more secure, due to of a greater amount of mesh material per unit area than is present for the central portion of the major or broad faces of the panel.
The fibres in a non-woven mesh for reinforcing a longitudinal marginal edge may be either randomly distributed or orientated. In the first case the longitudinal edges of the board will have substantially the same breaking strength in the longitudinal and the transverse directions. In the latter case, the longitudinal edges of the board can have high strength in the transverse direction but a lower strength in the longitudinal direction or vice versa. Thus, by varying the tissue characteristics, the edges may be made stronger in a particular direction, or additional strength can be provided in desired locations, e.g. along the board edges, by using tissues of appropriate fibre distribution.
The mesh size and the fiber diameter for a non-woven oriented mesh used to reinforce the longitudinal marginal edge face adjacent the longitudinal edge face may also be selected according to the strength desired in the longitudinal edge. However, a mesh for a longitudinal edge margin face may for example have a tighter weave or intercices than is used for the broad faces, i.e. for example a thread or mesh count tighter than 10xc3x978. Thus the reinforcing meshes for the marginal edge faces may have relatively small openings such as for example meshes with a 16xc3x9710 count per inch may be used so as to secure the desired or necessary penetration of the fabric along the edge margins with the cementitious composition.
The nonwoven mesh for reinforcing a longitudinal marginal edge may for example comprise fleece-like mats or felts of fibers arranged in a non-oriented manner. The nonwoven non oriented mesh reinforcing material may be three dimensional in nature with the fibers thereof defining interconnecting voids. In general, the non-oriented mesh which may be employed in the reinforcement of the longitudinal marginal edges are generally those in which the voids are relatively small in size, i.e. the fibers in the mesh, mat or felt are relatively tightly packed, e.g. of 2 to 4 oz. Per square yard.
A mesh for reinforcing a longitudinal marginal edge may be of a material as described above for the mesh for reinforcing the broad face of a panel. Such a mesh may, for example be of a synthetic material (i.e. polymer) such as described above; it may in particular be of polypropylene or of a polyester. The fibers in the non woven mesh, may be held in place by needle punching or, in the case of fibers derived from synthetic material such as an above describe polymer, by melt bonding or glueing (with a suitable adhesive) of the individual fibers to each other at points of intersection.
Illustrative of the non-woven spatial fabrics which can be employed in preparing the structures of the invention is the material synfab which is described herein below;
If desired the mat may be a mixture of two or more different types of fibre, or two or more mats of different fibrous material may be used.
The fibres in the mat may be multi-filament or monofilament.
It is preferred to use meshes that are flexible, and for this reason it is preferred to use relatively thin mats having a maximum thickness of the order of about 0.5 mm to 1 mm (e.g. up to 0.2 mm) and to use meshes made of relatively thin fibres, e.g. having a fibre diameter of no more than 1 mm in particular no more than 0.2 mm (i.e. 200 microns).
A reinforcing mesh whether for the broad faces or for the longitudinal marginal edges may be bonded to the core in any suitable fashion keeping in mind the reinforcing role that these meshes are to play. A reinforcing mesh may for example be bonded to a core by a cementitious slurry, for example, a portland cement slurry, or may be bonded by a cementitious component of a core mix extending through the openings in the mesh.
In accordance with the present invention a longitudinal edge face of a longitudinal marginal edge (i.e. a minor side face of a panel) need not be reinforced with or be covered with a reinforcing fabric. If, for example, a longitudinal edge margin is reinforced with a U-shaped reinforcement mesh component the bridge member thereof need not, if so desired, be adhered to the longitudinal edge face; on the other hand the bridge member may, if desired, be adhered to a longitudinal face as, for example, by an adhesive, by cementing or by being embedded in the core surface cement material. As may be appreciated from the above a bridge member links or connects a pair of arm members (i.e. edge strip members). These arm members are adhered to a marginal area of a respective broad face. However, such adherence need not be over the entire lateral width thereof. For example, a marginal area may comprise a grip region and an adhesion free region. The adhesion free region may border the longitudinal edge face. In this latter case an arm member may be adhered only to the grip region and not to the adhesion free region such that the cross section of the marginal edge may show that a U-shape surface including the surface of the longitudinal edge is not adhered to the U-shaped reinforcement mesh component, distal end portions only of the arm members are adhered to the marginal edge faces. Keeping in mind that the purpose of the U-shaped reinforcement mesh component is to reinforce the longitudinal edge of a panel the lateral width of a grip region is preferably larger (e.g. substantially larger) the lateral width of an adhesion free region bordering the longitudinal edge face.
The reinforcing mesh of the major faces and a mesh disposed about a longitudinal marginal edge faces may, for example, be held in place in the set product by allowing a cementitious composition to infiltrate intercices of such a mesh such that at least some of the fibers of the mesh may be embedded in the hardened cementitious composition. In this case in order to facilitate such penetration of a mesh by the cementitious composition, the fabrics should comprise a sufficient or desired degree of voidage so as to allow the unhardened cement composition to penetrate the mesh. In other words, a reinforcing mesh adhered to a broad face of a core and at least the portion of an edge reinforcing mesh adhered to a core along a marginal area thereof may be pervious meshes (i.e. pervious to cementitious slurry); the openings in a mesh, scrim or other fabric in this case are to be sufficiently large to permit passage of the mesh bonding material such as a portland cement slurry, i.e. such that a mesh or scrim is cemented to or embedded in a face or surface.
In accordance with the present invention a cementitious panel may be produced employing a core mix alone or if desired by also employing a cementitious slurry.
By way of example only, a cementitious panel in accordance with the present invention, may be obtained by following the immediately herein below described steps. A first web of reinforcing mesh may first be provided for a core face which during manufacture forms part of the bottom layer of the panel and which is not as wide as the panel width. A marginal section or area of the first web on each side of the centre may be disposed to overlap a portion of an edge reinforcing web or mesh of fabric leaving outer edge portions thereof uncovered thereby; the uncovered portion may be folded over to wrap each of the two edges of the core layer and also to extend over on to the top face of the core layer and overlap the upper broad face reinforcement mesh. A cementitious slurry may first be applied onto the first web so as to embed it therein and may be applied so as to leave uncovered at least an outer portion of the edge reinforcing webs for covering the longitudinally edge faces. The centre section of the first web receives the core layer after the application of the slurry if used and it also may be laid down so as to leave exposed outer marginal portions of the web or mesh to be wrapped about the longitudinal edges. A second web of reinforcing fabric (which forms the top layer of the panel) which is of the same width as the first web may be laid down on top of the core layer so as to overlay it and as desired or necessary is pushed just under the upper surface of the core so as to be embedded in the top surface. Bonding material such as a portland cement slurry may also as desired or necessary is applied to the second web either before or after it is laid down on the core layer.
A core mix may for example comprise water, a cementitious material (i.e. a hydraulic cement which is able to set on hydration such as for example, portland cement, magnesia cement, alumina cement, gypsum, and the like or a blend thereof) and an aggregate component selected from among mineral and/or non-mineral (e.g. organic) aggregate(s). The ratio of mineral aggregate to hydraulic cement may be in ratio of 1:6 to 6:1. The ratio of non-mineral aggregate to hydraulic cement may be in ratio of 1:100 to 6:1.
The particle size distribution of the aggregate may vary over a wide range e.g. up to about ⅓ (e.g. up xc2xc) of the thickness of the panel or smaller, such as for example from {fraction (1/32)} of an inch to xc2xc of an inch.
The core mix may in particular be composed so as to comprise a lightweight mineral and/or non-mineral (e.g. organic) aggregate(s) (e.g. sand, expanded clay, expanded shale, expanded perlite, expanded vermericulite, expanded closed-cell glass beads, closed-cell polystyrene beads and/or the like). Suitable lightweight aggregates, may for example in particular be cellular in nature; a suitable non-mineral lightweight aggregate is for example expanded closed-cell polystyrene beads.
Aggregate for use in the cementitious core mix composition may be selected in accordance with the desired density of the finished panel. Aggregate may, for example, have a density of up to 120 pounds per cubic foot. For example, lightweight aggregates such as obtained from expanded forms of slag, clay, shale, slate, perlite, vermericulite and the like may produce panels having a density of from about 80 to about 115 pounds per cubic foot. On the other hand a material such as closed-cell glass beds or a plastic such as polystyrene beads may be used to obtain a panel having a density of from about 40 to 70 pounds per cubic foot or lower.
A cementitious slurry may for example comprise water and a cementitious material (i.e. a hydraulic cement as described above). A cementitious slurry, such as a portland cement slurry, is strongly basic or alkaline having a pH of at least 11, due to the presence of calcium hydroxide, e.g. a pH of from 11 to 14, such as a pH of 11 to 13, e.g. a pH of 12.5 to 13. Such a slurry tends to react with, or have an affinity for, base-reactive surfaces and consequently have a decided tendency to cling to these surfaces.
As mentioned above a reinforcing mesh is adhered to the face of a panel. It possible in accordance with the present invention for example to embed a mesh in a broad or narrow face of the core such that the mesh is disposed at or near the surface of the board so as to enhance the strength of the board or panel, i.e. the strength of the panel is enhanced if a mesh is adhered at a core face. The embedment of the reinforcing fibers just beneath the surfaces of the core may for example be carried out at a depth of submersion of mesh from for example about 0.5 mm to about 2.0 mm or less, e.g. 0.5 mm or less.
The core mix may be applied in any desired thickness, for example of values so as to be able to obtain a panel having the standard thicknesses of plasterboard. A panel may be produced in varying thickness depending upon end use: e.g. in thicknesses of xc2xcxe2x80x3, xe2x85x9cxe2x80x3, xc2xdxe2x80x3, ⅝xe2x80x3, xc2xexe2x80x3, 1xe2x80x3 etc.
In accordance with the present invention a cemetitious core mix composition may be used which when cured has cells present due to entrained or entrapped air. Accordingly a core mix may for example include or comprise a suitable air entrainment or foaming agent in such amounts so as to produce the desired or necessary degree of air entrainment.
As mentioned above the initial side edge meshes and first broad face mesh are laid down on a suitable carrier support web; the carrier support web may for example advantageously be of a non-stick material relative to the cementitious material, i.e. the carrier on which the board is formed may be of a material to which the cementitious slurry does not readily adhere, example material are polyethylene or polypropylene film, 1.0 to 5.0 mils think: polyethylene coated Kraft paper, 30 lbs to 100 lbs of strength.
As mentioned above however it may be desired to provide an edge face mesh which is not adhered to the edge face so as to avoid having the cementitious composition covering up a desired indica which is to appear on the side edge of a panel. This may be achieved for example by providing the above mentioned edge reinforcing web with an at least substantially water impervious outer surface opposite the edge face or with a fibre or filament structure which may filter out any solids at the surface thereof so as to inhibit a mechanical bond on setting of the cementitious material.
The edges reinforcements may, for example extend inwardly from a longitudinal edge face approximately 0.5xe2x80x3 to 2.5xe2x80x3.
As mentioned above polystyrene may be used as lightweight aggregate. Polystyrene should be expanded following manufacturers instruction. Bin and equipment must be of the sufficient size to comply with the production rate and the time/recipe requirements. Polystyrene preferably is expanded to the desired density with a tolerance of 0.1 lb. per cubic foot. Anti-static liquid dispensing equipment may be provided for a free flow of material into measuring bins. Rotary valves will permit the incorporation of the necessary quantity in the core mixer, e.g. to the nearest 0.01 Kg.
As mentioned other agents may be added to the cementitious material for example, an air entraining agent. Air entraining agent works like a soap except it is able to create very small air bubbles that are visible only with a microscope. The air entraining agent is not necessarily used to make the board lighter. A given amount of a specific type of air entraining agent may be chosen to create air bubbles which will inhibit damage that can be caused by freezing and thawing cycles. The bubbles may be so small that water does not have a tendency to penetrate them, so the water absorption of the board is not affected.
A panel in accordance with the present invention may thus comprise relatively thin surface reinforcement elements on the faces thereof so as to provide the panel with a relatively high strength. The panel may also have a core which is relatively readily penetrable by nails, screws and other fasteners. A panel may be obtained wherein the surface edge reinforcement layers are relatively strong and hard such that a nail or screw may be driven through the edge of panel without pre-drilling and without breaking, even when nailed or screwed almost at the very limit of the edge of the panel.